关于家庭的英文儿歌:smith degradation是什么？生物化学里面的，

Smith降解实际上是一种改良的过碘酸氧化，它是将多糖过碘酸盐氧化，NaBH4还原后用弱酸部分水解 (通常在室温下用稀无机酸水解还原产物)，生成具有特征性的糖连接的重复单元，从而获得更多的结构信息。
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Smith 降解反应：将氧化完全的反应液，加乙二醇以分解未反应的 NaIO 4 ，透析 24h ，浓缩后用 KBH 4 还原，放置 12h 用 1 ％醋酸调至 pH ＝ 5 ，透析 24h ，浓干。用 2mol/l 三氟乙酸 100 ℃水解 12h ，中和后浓液作纸层析检测：展开剂为正丁醇－乙醇－水，溴甲酚紫显色。
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http://www.casper.organ.su.se/sop/sop101.html

Smith degradation
Introduction
The Smith degradation aims at selectively degrading a polysaccharide to either a polysaccharide with a smaller repeat or an oligosaccharide, from which structural information can be deduced. The procedure involves three steps, oxidation with periodate (IO4-), reduction to a polyalcohol with borohydride (BH4-) followed by hydrolysis with dilute acid under mild conditions, normally room temperature. During the hydrolysis step only acetals of oxidised sugar rings are supposed to be cleaved. The product may range from a monosaccharide glycoside to a polysaccharide. The following molecular fragments are susceptible to oxidation.

http://www-ermm.cbcu.cam.ac.uk/smc/swf001smc.htm